Rising, falling, and change triggers in Arduino - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does a rising trigger detect in Arduino interrupts?

A rising trigger detects when a signal changes from LOW (0 volts) to HIGH (usually 5 volts). It's like noticing when a light turns on.

beginner

Explain a falling trigger in Arduino interrupts.

A falling trigger detects when a signal changes from HIGH to LOW. Imagine noticing when a light turns off.

beginner

What is a change trigger in Arduino interrupts?

A change trigger detects any change in the signal, either from LOW to HIGH or HIGH to LOW. It's like noticing any switch flip.

intermediate

How do you attach an interrupt with a rising trigger in Arduino code?

Use attachInterrupt(digitalPinToInterrupt(pin), ISR, RISING); where ISR is your interrupt function.

intermediate

Why use interrupts with rising, falling, or change triggers instead of checking pins constantly?

Interrupts let the Arduino react immediately to signal changes without wasting time checking pins all the time. This saves processing power and makes your program efficient.

Which trigger detects when a signal goes from LOW to HIGH?

A Rising trigger

B Falling trigger

C Change trigger

D No trigger

A rising trigger detects the signal changing from LOW to HIGH.

What does a falling trigger detect?

A Signal stays HIGH

B Signal changes from HIGH to LOW

C Signal changes from LOW to HIGH

D No change in signal

A falling trigger detects when the signal changes from HIGH to LOW.

Which trigger reacts to both rising and falling edges?

A Change trigger

B Falling trigger

C Rising trigger

D None

A change trigger reacts to any change, either rising or falling.

What Arduino function is used to attach an interrupt?

A pinMode()

B digitalRead()

C attachInterrupt()

D interruptAttach()

attachInterrupt() is used to set up interrupts on pins.

Why are interrupts useful compared to checking pins in a loop?

A They disable other functions

B They waste power

C They slow down the program

D They allow immediate reaction to signal changes

Interrupts let the Arduino react immediately without constantly checking pins.

Describe the difference between rising, falling, and change triggers in Arduino interrupts.

Think about how a light switch turning on or off relates to these triggers.

Explain why using interrupts with these triggers can make your Arduino program more efficient.

Compare checking a door constantly versus having a doorbell that rings when someone arrives.